XENON10/100 dark matter constraints in comparison with CoGeNT and DAMA: Examining the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi mathvariant="script">L</mml:mi><mml:mi>eff</mml:mi></mml:msub></mml:math>dependence

Abstract

We consider the compatibility of DAMA/LIBRA, CoGeNT, XENON10 and XENON100 results for spin-independent (SI) dark matter weakly interacting massive particles, particularly at low masses ($\ensuremath{\sim}10\text{ }\text{ }\mathrm{GeV}$), assuming a standard dark matter halo. The XENON bounds depend on the scintillation efficiency factor ${\mathcal{L}}_{\mathrm{eff}}$ for which there is considerable uncertainty. Thus we consider various extrapolations for ${\mathcal{L}}_{\mathrm{eff}}$ at low energy. With the ${\mathcal{L}}_{\mathrm{eff}}$ measurements we consider, XENON100 results are found to be insensitive to the low-energy extrapolation. We find the strongest bounds are from XENON10, rather than XENON100, due to the lower energy threshold. For reasonable choices of ${\mathcal{L}}_{\mathrm{eff}}$ and for the case of SI elastic scattering, XENON10 is incompatible with the DAMA/LIBRA $3\ensuremath{\sigma}$ region and severely constrains the 7--12 GeV WIMP mass region of interest published by the CoGeNT Collaboration.